What a difference a millisecond can make. When it comes to browsing the web, every tiny moment counts — and the fewer moments that pass between a mouse click and a fully loaded page, the better.

Speed is a bit of an obsession for most web users. We fret over our Internet connections’ and mobile connections’ perceived slowness, and we go bananas for a fasterwebbrowser.

Given this better-faster mentality, the consequences for slow-loading pages can be dire for site owners; most users are willing to navigate away after waiting just three seconds, for example. And quite a few of these dissatisfied users will tell others about the experience.

What’s more, our entire perception of how fast or slow a page loads is a bit skewed. While we’re waiting for a site to materialize in a browser tab, pages seem to load about 15% slower than they actually do load. The perception gap increases to 35% once we’re away from a computer.

But for the precious milliseconds site owners can shave off page load times, they can see huge returns. For example, Amazon.com increased its revenue by 1% for every 100 milliseconds of load time improvement. And Aol said its users in the top 10% of site speed viewed around 50% more pages than visitors in the bottom 10%.

Site optimization firm Strangeloop has provided us with a slew of graphically organized stats on just how long pages take to load, why they take as long as they do, and just how long the average Joe or Jane is willing to wait around for your site.

How to perform a 5-minute page speed/revenue analysis of your ecommerce site

I proselytize the value of performance for a living. I am a member of the tribe that believes, beyond a shadow of a doubt, that improving the performance of your website will make you more money. I have dozens of stats at my disposal to convince you, and I feel an evangelical need to save non-believers from their errant ways.

Sometimes I’m confronted by non-believers who have the audacity to question my army of statistics and feel that the results at Amazon, Bing, Microsoft, Ebay, Shopzilla, AutoAnything, etc. do not apply to them.

I was confronted with one of these non-believers last week. In this case, he was a non-believer who was open enough to spend time brainstorming how the data could be presented in a way that would be more convincing. I am proud to say that he came out the other side as a serious performance convert. I want to share his conversion story.

“These stats don’t apply to me.”

I hear this a lot and I get it. It’s difficult for mortal companies to see themselves in relation to ecommerce mega-giants like Amazon and Ebay. This is why we put together stats on mortal companies.

But even those stats didn’t feel comparable for my skeptical comrade. He wanted to get an idea for how his site speed affects his users on his site with his content. Fair enough. My challenge was to figure out how to do this.

The obvious answer was to just implement Site Optimizer, speed things up, then check out conversion rate changes using a segmentation test, but this wasn’t an option. He needed to get buy-in before we could run a test implementation.

It was a chicken-or-the-egg conundrum. After much discussion, we decided to find proxies in his current analytics program that might convince him that performance would make him more money.